MOSCOW, Russia (CNN) -- A masked man shot and killed on Monday a Russian human rights lawyer known for his work on abuses by the Russian military in the breakaway region of Chechnya, Russian media reported.

The gunman also shot Anastasia Baburova, a journalist from Russia's Novaya Gazeta newspaper, when she tried to intervene. Baburova died later in a hospital.

Attorney Stanislav Markelov held a press conference earlier in the day opposing the early release of Col. Yury Budanov, who had been convicted of strangling a Chechen teenage girl. Budanov was released after serving only half his jail term.